Segmental myocardial displacement and tissue velocity analysis of the right ventricle in hypoplastic left heart syndrome fetuses and controls using-Color Tissue Doppler Imaging (C-TDI)

Introduction
The long-term outcome of patients with HLHS (hypoplastic left heart syndrome) is mainly determined by right ventricular function. Our study examines, whether there are differences in segmental right ventricular myocardial displacement and tissue velocities of fetuses with HLHS compared to healthy fetuses during gestation.

Material and methods
A prospective study was conducted including 20 fetuses with HLHS and 20 gestational age matched controls. c-TDI (colour tissue Doppler imaging) derived systolic and diastolic velocities as well as myocardial displacement were assessed in three different locations of the right ventricle (RV). A ROI (region of interest) was placed in the basal, middle and apical part of the myocardium. Possible changes of c-TDI indices in the course of pregnancy and between the three different segments were investigated in both groups.

Results
HLHS fetuses showed significantly lower e' velocities measured in the basal and middle part of the RV compared to healthy controls (p < 0.05). Basal displacement showed significantly lower values in HLHS fetuses compared to controls. In control fetuses but not in HLHS fetuses there was a significant increase of basal diastolic velocities and displacement in the course of pregnancy. According to myocardial velocities and displacement values there was a significant decrease from the base of the fetal heart to the apex pointed in both groups.

Conclusions
An altered right ventricular myocardial function in HLHS fetuses within different myocardial segments could be demonstrated. An apicobasal gradient with higher velocity and displacement values in the basal part of RV myocardium could be found in both groups. The technique may be of value in the prenatal assessment of myocardial function, however its role as a monitoring tool and outcome predictor needs to be defined.